This invention relates to a gasoline vapor recovery system and, more particularly, to a system which assures proper connections for the vapor recovery hose used in making bulk gasoline delivery.
When underground gasoline storage tanks at service stations are filled a substantial volume of air loaded with gasoline vapors, which is a source of pollution, is displaced from the storage tank at a high rate. As the compartments on the gasoline tank trucks are emptied air is drawn into those compartments to replace the gasoline discharged from them.
The present system eliminates the need for an orifice and pressure vacuum valve on the storage tank vent and, in addition, significantly deters any tendency to release pressure from the storage tank when the vapor hose is not connected by blocking open the dry break valve on the underground tank vent riser. The latter is of particular importance because of the severe hazard of venting gasoline vapors from the underground storage tank at ground level.